MathDB
ab+1,bc+1, cd+1, da+1 simultaneously perfect square

Source: Danube 2012 junior p1

July 22, 2019
Perfect SquaresPerfect Squarenumber theory

Problem Statement

a) Exist a,b,c,∈Na, b, c, \in N, such that the numbers ab+1,bc+1ab+1,bc+1 and ca+1ca+1 are simultaneously even perfect squares ? b) Show that there is an infinity of natural numbers (distinct two by two) a,b,ca, b, c and dd, so that the numbers ab+1,bc+1,cd+1ab+1,bc+1, cd+1 and da+1da+1 are simultaneously perfect squares.